Posted
by
timothy
on Saturday February 06, 2010 @05:30AM
from the you-must-become-the-frozen-water dept.

ccktech writes "As reported by NPRand Chemistry world, the journal Science has a paper by David Ehre, Etay Lavert, Meir Lahav, and Igor Lubomirsky [note: abstract online; payment required to read the full paper] of Israel's Weizmann Institute, who have figured out a way to freeze pure water by warming it up. The trick is that pure water has different freezing points depending on the electrical charge of the surface it resides on. They found out that a negatively charged surface causes water to freeze at a lower temperature than a positively charged surface. By putting water on the pyroelectric material Lithium Tantalate, which has a negative charge when cooler but a positive change when warmer; water would remain a liquid down to -17 degrees C., and then freeze when the substrate and water were warmed up and the charge changed to positive, where water freezes at -7 degrees C."

I thought pure water doesn't go solid, not until an impurity starts crystal formation that turns the water into a solid?

This comment seems really unintuitive so I looked around a little. Ice [wikipedia.org] can actually form entirely without crystallization, by cooling it to ~137 C in a matter of milliseconds. The article also mentions that "pure water, in the absence of any nucleating surface, can remain in a supercooled liquid state down to temperatures as low as
-40C". I guess that means that pure water will begin crystallizing at this temperature anyway.

Exactly, this is well known, and is the difference between homogeneous nucleation caused by the massive undercooling providing the energy to nucleate ice spontaneously versus heterogeneous nucleation which requires much less free energy and occurs dependent on surfaces.

It is not scientifically interesting that they warmed it to get it to freeze, that's just a comparison of freezing points... it's interesting that the charge of the surface modified the freezing/nucleation point. Frankly, I am amazed that this was published in Science; it seems like worthwhile research, but for a journal more like, say... applied physics letters or a more specific interest journal. Kudos to the researchers for managing to spin it as a general-interest paper when it is in fact a fairly simple observation of an obscure phenomena.

I realize that I'm ignoring lots of physical detail, but like others above I remain unimpressed by the ability to freeze water at 137 degrees below its freezing point. It won't help my radiator on a cold day, unfreeze my pipes or the walk outside, as those environments don't have the purity and perfection required to get away with this.

Can someone offer an example of a useful application of the ability to freeze pure water at -137 degrees? Someone must have taken advantage of this property to do something

Actually, liquid water already contains quite a lot of tetrahedral "crystalline" structures floating around amongst the other molecules. So it really shouldn't need anything external to crystallize around... it already has some of its own.

So you are saying that even in a "liquid" state, water has crystals that have formed? Fascinating. It truly amazes me how little we know about water and how we keep discovering new things about it. There are a lot of quacky people that think the homeopathic effect works, but if you ask me, it really sounds like pseudo-science. The placebo effect may actually be more powerful, so what does that say?

Defects in the container can help it to freeze. It can also help to prevent superheated water in the microwave. I've come close to being burned by this effect.

I remember one time when younger smashing the ice in a puddle with my foot while running and the water underneath making a cracking sound after a second. It was odd enough for me to stop and look. It had frozen solid in an instant. It had a odd pattern to it but I was more interested in getting to some place warm so I didn't really stay and examine it

I had something like that happen to me. Most people I mention this to think I am bullshitting them. About 20 years ago I had put a filled plastic bottle of water in the freezer to take with me on a hike the next day. The next morning I opened the freezer and pulled out the water bottle. To my surprise, it was clear as glass. I was a little confused wondering if this was my bottle when my thumb made an indentation in the plastic. Within about

Water needs to reach the correct temperature and then have something trigger the phase transition.

In other words:
The crystallization has to start somewhere. Imperfections in the surface or impurities supply this. If you have very pure water and a "perfect" container, the lack of a starting point for crystallization can delay the phase transition by quite a bit.
(Then you get YouTube videos showing flash freezing of water bottles!/i))

Salt and anti-freeze just have typical freezing-point depression; there's no way to use them to produce a situation where water that is a stable liquid at one temperature will turn solid if you increase the temperature. The situation in this experiment is that water that's liquid at -17 C will freeze as you head it up towards -7 C.

But it wasn't really a difference in the water, it was a difference in the container around the water. That is a well known phenomenon with airborn freezing temperature water, that it freezes on impact instead of while traveling through (clean) air.

you can replicate it yourself, leave a water bottle out in the garage when it's about 20 F out. take it inside and smack it against your hand, if the temperature is right you can watch the ice form. it works even better with non-carbonated flavored waters.

You are correct about the humidity in the air, and how the most obvious effect of that (at least to those of us in colder climes) is the formation of black ice on the road... but I think the interesting part of this experiment isn't that they were able to cause the water to freeze by raising the temperature from -17'C to -7'C, it's how they were able to do it. Namely, that the freezing point of water changed based on the electric charge of the surface the water is on. Shouldn't really come as a surprise, as

Amen. This has nothing to do with changing the temperature of the water and everything to do with changing the charge on the container (which happens to be a function of temperature). It would be interesting to replicate this experiment on a piezoelectric rather than pyroelectric medium and force the water to phase change by deflecting one surface of the container a bit.

You missed the point. The neat thing is that water was liquid, and then they WARMED it, and it froze. It is just a gimmick, but it's not just that they managed to get it to freeze at a temperature below 0C. It's that, due to the interaction between temperature, charge, and the freezing point, they reversed the normal COLD-WARM SOLID-LIQUID order.

You missed the point. The neat thing is that water was
liquid, and then they WARMED it, and it froze. [...] they reversed the
normal COLD-WARM SOLID-LIQUID order.

In this supercooled
water experiment [youtube.com]
video, notice that the supercooled water freezes after
the bottle is tapped. So energy is put into it, meaning
that it is warmed up slightly.
Isn't this also reversing the cold-warm solid-liquid order?

NO. You can also "reverse the cold-warm solid-liquid" order by changing the pressure. This is ridiculous. The title makes it sound like you can just warm up water and make it freeze. And people are actually arguing that it's amazing. The changed the temperature while simultaneously changing another variable. That's cheating.

Exactly. They didn't JUST warm the water, they changed the surrounding conditions at the same time. While I wouldn't necessarily say it's "cheating" (because they weren't even trying to freeze the water by "just" warming it up), it certainly wasn't freezing water by warming it.

Doesn't look very much like supercooled water. Atleast two details are missing. First, if it was supercooled, I would assume condensed water droplets on the surface of the bottle, or frost. Also, if it actually was frozen water, the bottle should expand as the ice takes up more volume than liquid water. It most likely is sodium acetate dissolved into water.

Yeah, and if you pull a certain amount of vacuum on it, you can get water to do all of boil, liquefy and freeze [wikipedia.org] at the same temperature. This is even without applying mechanical energy or kinky fields (electrostatic or magnetic) to coerce its behavior.

It's been quite a while since I've thought about "extreme" computer cooling solutions, but I thought Fluorinert was just a non-conductive liquid that otherwise was quite water-like. I used good old dollar-a-gallon distilled water in my old watercooling setup and that worked perfectly well.

Of course skimming Wikipedia tells me that you can get some with very low boiling points, but you wouldn't usually use evaporative cooling for computers (I've seen it done, but it's impractical at best; downright dangerou

In various parts of the world where you have unreliable power and a need for cooling, the ability to cool without massive draws is a huge benefit especially in the medical community. The other option is to use clay, but that can get messy after abit.

I doubt you would want to coat your water pipes with Lithium Tantalate. First, tantalum is very expensive, and second (though this is only a wild guess) it could very easily be poisonous. Lithium can be pretty nasty stuff, and I don't know about tantalum.

I don't remember the science story yesterday Physicists Discover How To Teleport Energy being called Japanese Physicists Discover How To Teleport Energy. Is the fact these scientists are Israeli title worthy?

Modded very funny, but with some element of truth. The grandest experiments in physics often require significant international collaborations and highly specialized instrumentation (think Large Hadron Collider) that demand large-scale pooling of resources. On the other hand, at least at this time, there really are no projects with such requirements in chemistry. Sure, there are many vibrant chemistry collaborations, but not nearly of that scope. So you can easily end up working only with people nearby, comp

I don't remember that stories about Italian/Japanese/German/British/French/Canadian scientists were ever questioned for mentioning the country of origin. Is the fact these scientists are Israeli disturbing you?

I don't find it particularly disturbing. I was pointing out the examples for the opposite reason--- to suggest that "[Nationality] Scientists" is not a particularly unusual phrase, contrary to the claims of the poster I was replying to.

Maybe it's confirmation bias, but I've seen this over and over in "Israeli X does Y" articles on slashdot (eg. Intel engineers coming out with a cool new chip). I've yet to see the complaint launched at Norwegians.

Your hypothetical situation isn't parallel precisely because it didn't happen. If it did happen, then you have a point.

Just wanted to point out that rubbish such as organ harvesting isn't particularly new - unless you count switching from Christian kids to Palestinian Arabs as some kind of creativity.

People, after all, believe what they want to believe. 700 years ago it was a little harder - a pastor had to work hard to convince his followers that their Jew neighbors are "organ harvesting vile psychopaths". Today it's enough to show a photo of a bunch of cow hearts and everyone goes berserk.

Cow hearts? Oh, stop it. I'm not talking about 700 year-old religious propaganda aimed at the poor, long-suffering Jews who must never be evaluated in the same light as any other war criminal, (because they're special!) I'm talking about Israel's chief pathologist being investigated for organ harvesting. [israelnationalnews.com] And you know it.

As a side note - who is exactly this "government" you're talking about? I was sure it is democratically elected. And replaced every 2.5 years in average, by the way. So - unless everyone here is a psychopath (a wonderful word, by the way), eventually we will run out of psychopathic governments. Shame. Where will I get my extra eye-balls then.

Well, THAT was the lamest piece of 'logic' I've heard today. Congratulations. Are you telling me that "Democracy" prevents corruption? I think the grand experiment in America has pro

Indeed. I remember something that I think I heard Chomsky saying, it might have been in response to one of those silly people that claim science is just like religion, and he mentioned something about the Nazi term Deutsche Physik and how that was silly, as when he reads a well written scientific paper he has no idea about the culture or religion of the author as science aims for objectiveness and tries to avoid subjectiveness. It shouldn't matter one bit who is doing the science, their name, country or eth

When I put a beer in the freezer too long but not that long, when I take it out of the freezer, I can see it is pretty 100% liquid inside the bottle. Now, taking it out of the freezer makes it warmer and opening it even warmer due to air circulation inside the bottle.

Well, when I open it, it turns to ice so I make my beer freeze by making it warmer so nothing new here;--))))

Very seriously, I swear this is true but I understand it could be due to other factors that the ones described in TFA like pressure inside the bottle but I thought it would interesting to mention anyway.

Haven't anybody else seen their beer freeze in their hand while opening it just after it has been in the freezer although it was in a liquid state when they actually took it out of the freezer ?

Good beer is NOT about the amount of alcohol, it is about the flavor. If it has low alcohol, you just can drink more of it. Granted, the better tasting beers tend to have high alcohol content, but I am sure that is just a coincidence. As is the fact that my new driving license has "revoked" pre-stamped across it.

I think he was referring to the fact that it tastes like fizzy water with beer-like flavour, not the alcohol content. And Budweiser tastes pretty darned watery, even compared against other beers of the same type. Ales usually have a heavier taste to them, so it's not really fair to compare Budweiser against something like Guiness or Caledonian in terms of flavour. It is, however, fair to compare it against a good lager like Pilsner Urquell. Even when you compare it against a shitty lager, like Labatt Blue (which is also a pilsner, like Budweiser), Budweiser comes out on the bottom.

(and no, I'm not saying that Canadian beer sucks, just that some of the most popular Canadian beers suck. Namely, Labatt and Molson. If you want a good Canadian beer, try something like Steam Whistle, or Wellington. We don't export the good stuff. Similarly, I think the Australians are smart enough to export the shitty beers and keep the good stuff for themselves, as are the Dutch... think about that when you order a Fosters or a Heineken.)

Actually, your typical Budweiser is roughly around 3.4% alcohol by volume, which is quite weak. In the days before and during Prohibition it would have been scoffed at and called "Near Beer", made for kids. But it is that way today because of post-Prohibition laws that restricted beer to lower alcohol levels. In some states that is. For some reason around 3.3-3.4% was a fairly common level when it came to such laws.

My state used to have some weird laws carried over from those days. They have changed some

All I can tell you is that this state no longer regulates the percentage, but Budweiser and many other bulk process lagers in the stores here are still in the 3.3% to 3.5% range (not 3.2). And that is easy enough to tell because the law no longer prohibits display of the alcohol content. Some are marked on the containers, and some (though few) stores mark it on the shelves.

No, there is no county regulation. If there were, I still couldn't reach 2 feet further down and pull a 7% or 10% beer off the shelf.

The fact is that most (but by no means all) mass-produced beers in stores in my state are still in the 3%+ range, although no law requires them to be. I do not know why that is; I admit that I simply assumed that those mass-produced beers basically just distributed beer of those percentages.

I admit that there is something of a puzzle here. But I assure you that it is not

You could also supercool it I guess and shaking it a little when taking it out causes it to crystallize - but I'm having doubts about beer and beer bottles being pure enough to not crystallize out in the first place.

I've also seen this happen with regularity - at work we sometimes crack a beer after hours, my boss likes to keep his cube fridge hell-frozen-overishly cold. So perfectly liquid beers (can or bottle) from the top shelf often freeze within 20 seconds after opening. He swears by the belief that giving the can a good hard squeeze for several seconds prior to opening reduces the chance of it freezing, but nobody has yet come up with a believable theory as to why that would be. Guesses so far are that the applyi

He must be negatively charged (thus keeping water a liquid on or in him) and then the moment he "releases" it, it freezes!

Could there be some sort of industrial application for this, like ice-making where you have a jet of "liquid" water (because it is kept in a negatively charged apparatus) but upon contact with something, loses its charge and freezes? How about rapid construction of ice sculptures? Just like spray on concrete.

I even seem to remember someone in WWII proposing making giant pontoons/floating islands out of ice and hay.

How about in Antarctica/on Mars using it for rapid construction of ice domes? Once it solidifies it won't melt.

That's why you apply a "top coat" of some sort of plastic to the ice once formed. Of course, all that ice sculpture does is protect one from an environment that is very cold but not very conductive and so easily protected against. It also would do nothing to maintain pressure inside the "bubble". Probably easier to just use plastic in the first place...

It sounds like it freezes due to the change in charge, not because the water warms up.

But when the water warms up, that causes the charge on the surface to change, thereby causing the water to freeze; so the water warming up, and it freezing, are causally linked. It seems more like a neat trick than anything else, but "freeze water by warming it" is a more-or-less accurate summary of what's happening.

So first they cool it to -17 degree and it remains a liquid, then they warm it up to -7 degree and it freezes. That's like traveling from Greenwich to the Arctic via Antarctica and then call it a scientific discovery that one can actually reach the Arctic by going south, right?